Stabilized Lithium, Manganese-Rich Layered Cathode Materials Enabled by Integrating Co-Doping and Nanocoating

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium, manganese-rich (LMR) layered oxide cathodes offer high energy density and low cost.
• LMR materials suffer from capacity and voltage decay due to oxygen migration and side reactions with aqueous electrolytes at high voltages.

Purpose of the Study:

• To enhance the structural homogeneity and electrochemical performance of LMR cathode materials.
• To develop a cost-effective surface modification strategy for LMR cathodes.

Main Methods:

• Integration of Na/F co-doping (CD) and AlF3 coating on LMR materials.
• Electrochemical performance testing (150 cycles at 0.5C).
• Spectroscopic and post-cycling analysis to investigate structural and chemical changes.

Main Results:

• CD with 1 wt % AlF3 (CD-1.0 wt %) demonstrated excellent electrochemical performance with 93% capacity and 91% voltage retention after 150 cycles.
• Increased ionic conductivity and alleviated rock-salt structure formation and Mn dissolution.
• Surface cobalt enrichment and partial Al3+ diffusion into the bulk created a stable Li(CoAl)O2 phase, minimizing metal segregation.

Conclusions:

• Na/F co-doping and AlF3 coating is an effective strategy to improve LMR cathode stability and performance.
• This approach enhances structural homogeneity, crucial for commercial viability.
• The study presents a novel method for LMR cathode modification without complex deposition techniques.